Gear teeth grinding apparatus



Oct; 14, 1958 s. 5. BOARD, JR

GEAR TEETH GRINDING APPARATUS Filed March 26, 1956 2 Sheets-Sheet 1 INVENTQR q M msw Oct. 14, 1958 S. 5. BOARD, JR

GEAR TEETH GRINDING APPARATUS 2 Sheets-Sheet 2 Filed March 26, 1956 INVENTOR -ATTORNEY5 United States Patent GEAR TEETH GRINlJlNG APPARATUS Samuel S. Board, Jr., Snyder, N. Y., assignor to Farrel- Birmingham Company, Incorporated, Ansonia, Conm, a corporation of Connecticut Application March 26, 1956, Serial N 0. 573,776

16 Claims. (til. 51-142) This invention relates to gear-grinding apparatus, and more particularly to an apparatus for grinding or finishing the teeth upon a gear blank by means of an abrasive belt or other traveling member having an abrasive surface and maintained in engagement with the tooth of a blank.

As illustrated, a traveling abrasive belt is employed and this belt is maintained in engagement with a tooth of the blank, the belt or operative portion thereof traveling in a rectilinear path. The belt is mounted upon a reciprocating carriage while the gear blank is mounted upon an oscillatable support, and means are provided to oscillate this support in timed relation with and through a distance proportional to the travel of the carriage upon which the abrasive belt is mounted.

In such an apparatus it will be apparent that the abrasive belt operates as a portion of one tooth of a simulated rack meshing with the teeth of the gear blank. Therefore, the edge of the belt must be maintained at substantially the distance of one half of the root diameter of the blank from the axis of the latter. Therefore, when gearsof different pitch diameter are employed, it is necessary to move the belt toward and from the axis upon which the gear blank rotates in order to secure proper engagement of the abrasive belt with the teeth of the blank.

In addition, it is necessary that the gear blank be 1'0- tated through a given arcuate or peripheral distance proportional to the linear distance through which travels the carriage upon which the abrasive belt is mounted. In other words, when the carriage moves a distance equal to one circular pitch on the gear blank, the latter must also rotate through a distance equal to one circular pitch.

To effect such an operation, the gear blank is mounted upon a rotatable table to the axis of which is secured a drum, which drum is oscillated by bands-connected at their ends to a pivoted bar. This bar is oscillated about its pivot by means of an arm connected to the carriage or in this instance connected to the movable base or support for the abrasive belt.

The connection between the pivoted bar and the arm carried by the belt-supporting member is a slidable one so that as the belt support is moved in and out toward the rotating table which supports the blank in order to grind gears of varying pitch diameter, the connection of the bar with the arm will be varied relatively to the pivot of the bar and thus vary the angle through which the gear blank is oscillated.

With this construction as the belt is moved toward and from the axis of the supporting table for the gear blank to accommodate gears of different pitch diameters, the angle through which the blank is oscillated will be automatically adjusted.

Also the connection of this arm with the pivot bar may be adjusted to accommodate gears of different diametral pitch; In other words, the arc through which the gear blank is oscillatedmay be varied with respect to the disice tance traveled by the reciprocating carriage independently of the adjustment of the abrasive belt toward and from the center of the gear blank which latter adjustment depends upon the pitch diameter of the gear.

One object of the present invention is to provide a gear-grinding mechanism which will be self-adjustable for the grinding of gears of various pitch diameters.

A further object of the invention is to provide a geargrinding apparatus having a grinding element such as an abrasive belt carried by a reciprocating carriage and a supporting table for the gear blank oscillated in synchronism with the reciprocation of the carriage, the arrangement being such that as the grinding element is fed toward or away from the axis of the gear blank to accommodate gears of diiferent pitch diameters, the angle through which the gear is oscillated will be automatically adjusted.

A further object of the invention is to provide a geargrinding machine of the character described with means for adjusting the angle through which the gear blank is oscillated in accordance with the diametral pitch of the gear blank being ground.

To these and other ends the invention consists in the novel features and combinations of parts to be hereinafter described and claimed.

In the accompanying drawings:

Fig. l is a front elevational view of a gear-grinding mechanism embodying my improvements, some parts being broken away for the sake of clearness;

Fig. 2 is a top plan view of the mechanism shown in Fig. 1;

Fig. 3 is an end elevational view with some parts being shown in section;

Fig. 4 is a sectional view on line 44 of Fig. 1;

Fig. 5 is a sectional view on line 5-5 of Fig. 2; and

Fig. 6 is a sectional view on line 66 of Fig. 2.

To illustrate an embodiment of the invention there is shown in Fig. 1 of the drawings a gear-grinding mechanism comprising base or frame portions 10 and 11, the portion 10, as will be hereinafter described, serving as a support for the grinding mechanism and the portion 11 serving as a support for the gear blank. A hollow shaft 12 is rotatably carried by suitable bearings within the base portion 11, this shaft carrying at its upper end a table or support 13 upon which may be secured the gear blank shown in dotted lines at 14.

Upon the base portion 10 are provided ways 15 upon which is slidably mounted a carriage 16, which carriage may be reciprocated by a piston and cylinder structure 17. As this method of reciprocating a carriage is well known in the art, no further description is necessary.

Upon the carriage 16 is mounted a tool support 1S, this support being slidably adjustable transversely of the length of the carriage, this adjustment being effected by a screw 20 rotatably mounted in the support and threadedly engaged with a lug 21 secured to the upper surface of the carriage. The screw may be rotated by means of the hand wheel 22 to move the support 19 toward and from the axis of the gear blank 14 (Fig. 3).

-Mounted upon the support 19 for rotatable adjustment is a tool carrier head 23, this head having a centrally located pin 24 received in a socket 253 in the tool support 19. The support 2E is provided with an arcuate slot 26 (Fig. 2) which receives a screw 27 threaded into the support 19 so that the carrier 23 may be rotatably adjusted about the axis of the pin 24 with respect to the carriage and the support 19 in order to provide nominal pressure angles to the teeth of the blank being ground. It will be understood that the screw 27 will lock the tool carrier 23 in any desired adjusted position, the slot 26 being concentric with the axis of the pin 24.

Secured to the carrier 23 is a frame or standard 29 having bearings at its upper and lower ends for the mounting of pulleys 30 and 31 around which the endless abrasive belt-grinding element 32 is trained. Also at the upper portion of the standard 29 is carried a motor 53 for driving the upper pulley andthe belt, the lower pulley serving as an idler.

The structure so far described is similar to the abrasive belt grinding mechanism shown in the patent to Warren C. Whittum, 2,736,994, dated March 6, 1956, and it will be apparent that when gears of different pitch diameter are ground, the tool support 19 may be moved toward and from the axis of the gear-blank-supporting table 13 as required. Also it will be apparent that when grinding gears of different pitch diameter, it is necessary to adjust the angle through which the table 13 is oscillated relatively to the distance traveled by the reciprocating table in order that the grinding element, in this instance the belt 32, may serve as a rack tooth in engagement with the teeth of the blank. The means by which this adjustment is effected automatically will now be described.

Secured to the shaft 12 of the table 13 is a drum 35, and two sets of bands are passed partially about the periphery of the drum and secured thereto. One set of bands is shown at 36 secured to the drum at the point 37 while the other set of bands 38 is secured to the drum at 39 so that each of the bands passes more than half way around the drum but not completely around it.

The other end of each of the bands of one set is secured to the whiffletree 40 while the other end of each of the bands of the other set is secured to the whiffletree 41 (Fig. Each of the whifiletrees is secured to a block slidably mounted in the part 11, these blocks being desig nated at 42 and the elements 40 and 41 being secured thereto by the screws 43. The blocks 42 slide in guideways 44 in the frame, these guideways being parallel to the direction of motion of the carriage 16.

As shown in Figs. 2 and 5, a pivot pin 45 is rotatably mounted in each of the blocks and secured to a slide 45* of channel-shaped formation, which slide slidably engages a bar 46 pivoted to the frame at 47 at a point midway between the two blocks 42. It will be seen that with this construction when the pivot bar 46 is oscillated about its pivot point 47, the bands 36 and 38 will be pulled first in one direction and then in the other and will serve to oscillate the drum 3S and the table 13 to which the drum is secured, thus oscillating the gear blank 14-. As the channel-shaped slide members 45 are pivoted to the sliding blocks 42 and slidably engage the bar 46, it will be seen that this bar will be permitted to oscillate and at the same time effect reciprocation of the blocks 42 in the slideways 44, thus moving the bands 36 and 38.

Means are provided to oscillate the bar 46 from the movement of the carriage 16. For this purpose an arm (Figs. 2 and 3) 49 is secured to the tool support 19 which it will be understood is fixed in position longitudinally of the carriage 16 although adjustable transversely thereof by the screw 20. This arm 49, as shown more especially in Figs. 5 and 6, is provided with a horizontally disposed end portion 56 within which is an elongated slot 51 slidably embracing a block 52. The position of this block may be adjusted within the slot 51 by the adjusting screw 53.

Rotatably mounted in the block 52 is a pin 54, the lower end of which is secured to a slide 55 of channelshaped formation, which slidably embraces the pivoted bar 46 (Fig. 5). Thus, it will be seen that the bar 46 may move pivotally with respect to the arm 49 by reason of the pivot pin 54 and also the arm 49 may be moved lengthwise of the pivot bar 46 due to the fact that the slide member 55 is slidably engaged with the bar.

From the above construction it will be apparent that as the carriage 16 reciprocates, the arm 49 will likewise reciprocate and effect oscillating movement of the bar 46. The amplitude of movement of this bar or the are 4 through which it is oscillated for a given travel of the carriage 16 will vary according to the distance of the pivot pin 54 from the pivot pin 47. As the work support 19 is moved toward and from the work, the slide 55 will be moved toward and from the pivot point 47, thus automatically adjusting the angle through which the bar 46 is oscillated, depending upon the pitch diameter of the gear blank. It will also be apparent that the movement imparted to the blank by the bands 36 and 38 will be dependent upon the travel of the blocks 42 so that the amplitude of the oscillating movements given the blank or the angle through which the blank is moved in its oscillating movement will be dependent upon, and equal to, the angle through which the bar 46 is moved. Thus when'the carriage moves through a distance of one circular pitch, the gear blank will also be rotated through a distance of one circular pitch.

Also it will be apparent that while the position of the slide 55 on the bar 46 is dependent upon the position of the grinding element 32 on the carriage in that the element 55 will be adjusted along the bar 46 with adjustments of the grinding element 32, the slide 55 is also adjustable independently of the position of the grinding element in order to adjust the device for gear blanks of different diametral pitch. This latter adjustment is obtained by the adjustment of the block 52 in the slot 51 by means of the screw 53. Thus the device may accommodate gears of different pitch diameter as well as gears of different diametral pitch without substitution of different parts such, for example, as the substitution of a different size drum 35.

It will be understood that the throw or travel of the carriage 16 in its reciprocating movements may be adjusted as is usual in tools of this general character. As this adjustment may be effected by the usual means, it has not been illustrated herein.

While I have shown and described one embodiment of my invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modification and variation within the spirit of the invention and within the scope of the claims.

What I claim is:

1. A gear-grinding machine having a frame and a reciprocating carriage, a grinding element mounted on the carriage for adjusting movements in a direction transverse to the direction of reciprocation of the carriage, an oscillatable work support for holding a gear blank to be ground, the axis of said work support being fixed with respect to the frame, means for effecting oscillation of said work support, and means for varying the amplitude of oscillation of the work support in response to the adjusted position of the grinding element on the carriage.

2. A gear-grinding machine having a frame and a reciprocating carriage, a grinding element mounted on the carriage for adjusting movements in a direction transverse to the direction of reciprocation of the carriage, an oscillatable work support for holding a gear blank to be ground, means mounting said work support for oscillation about an axis fixed with respect to the frame, means for effecting oscillation of the work support from the reciprocation of the carriage, and means for varying the amplitude of such oscillation responsive to the adjusted position of the grinding element on the carriage.

3. A gear-grinding machine having a frame and a reciprocating carriage, a grinding element mounted on the carriage for adjusting movements in a direction transverse to the direction of reciprocation of the carriage, an oscillatable work support for holding a gear blank to be ground, means mounting said work support for oscillation about an axis fixed with respect to the frame, a variable connection between the carriage and the work support to effect oscillation of the latter from the reciprocation of the carriage, and means for varying said connection by adjustment of the grinding element with respect to the' carriage to vary amplitude of oscillation of the work support.

4. A gear-grinding machine having a frame and a reciprocating carriage, a grinding element, supporting means for the grinding element, said supporting means being mounted on the carriage for adjusting movement in a direction transverse to the direction of reciprocation of the carriage, an oscillatable work support for holding a gear blank to be ground, means mounting said work support for oscillation about an axis fixed with respect to the frame, means for elfecting oscillation of the Work support from the reciprocationv of the carriage, and means for varying the amplitude of such oscillation responsive to the adjusted position of the grinding-element-supporting means on the carriage.

5. A gear-grinding machine having a frame and a reciprocating carriage, .a grinding element, supporting means for the grinding element, said supporting means being mounted on the carriage for adjusting movement in a direction transverse to the direction of reciprocation of the carriage, an oscillatable work support for holding a gear blank to be ground, means mounting said work support for oscillation about an axis fixed with respect to the frame, a variable connection between the carriage and the work support to effect oscillation of the latter from the reciprocation of the carriage, and means for varying said connection by adjustment of the grindingwheel-supporting means with respect to the carriage to vary the amplitude of oscillation of the Work support.

6. A gear-grinding machine having a frame and a reciprocating carriage, a grinding element mounted on the carriage for adjusting movements in a direction transverse to the direction of reciprocation of the carriage, an oscillatable Work support for holding a gear blank to be ground, means mounting said work support for oscillation about an axis fixed with respect to the frame, means for oscillating said work support by the reciprocation of the carriage, and means for varying the amplitude of oscillation of the Work support in response to, and also independently of, the adjusted position of the grinding element on the carriage.

7. A gear-grinding machine having a frame and a reciprocating carriage, a grinding element, supporting means for the grinding element, said supporting means being mounted on the carriage for adjusting movement in a direction transverse to the direction of reciprocation of the carriage, an oscillatable work support for holding a gear blank to be ground, means mounting said work support for oscillation about an axis fixed with respect to the frame, a connection between the grinding element supporting means and the Work support to effect oscillation of the latter from the reciprocation of the carriage, and means for varying said connection independently of the position of the grinding element supporting means on the work carriage to vary the amplitude of oscillation of the work support.

8. A gear-grinding machine having a frame, a carriage reciprocably mounted on the frame, a grinding-element support mounted on the carriage, a grinding element carried by said support, a work-supporting table oscillatably mounted on the frame in position to support a gear blank in engagement with the grinding element, a bar pivoted on the frame between its ends, means connecting points on said bar each side of its pivot to said table to oscillate the same upon oscillation of the bar, and means to oscillate said bar comprising an arm supported upon the grinding element support and connected to the bar.

9. A gear-grinding machine as in claim 8 wherein a drum is secured to said table, blocks slidably mounted in the frame to move in a direction parallel to the reciprocation of the table, bands secured to said drum at one end and having their other ends connected to said blocks, and said blocks being connected to said bar to be reciprocated thereby.

10. Agear-grinding machine having a frame, a carriage reciprocably mounted on the frame, a grinding-element support mounted on the carriage for adjusting movement in a direction transverse to the direction of its reciprocation, a grinding element carried by said support, a supporting table for a gear blank oscillatably mounted on the frame, a drum secured to said table, bands each secured at one end to said drum, a pair of slide elements slidably mounted in the frame to which the other ends of said bands are secured, means guiding said slide elements for movement in a direction parallel to that of the carriage, a bar to which said slide elements are slidably connected, said bar being pivoted on the frame between said slide elements, and means connecting said bar to the carriage whereby the bar is oscillated by reciprocation of the carriage and serves to oscillate said table.

11. A gear-grinding machine having a frame, a carriage reciprocably mounted on the frame, a grinding element support mounted on the carriage for adjusting movement in a direction transverse to the direction of its reciprocation, a grinding element carried by said support, a supporting table for a gear blank oscillatably mounted on the frame, a drum secured to said table, bands each se-' cured at one end to said drum, a pair of slide elements slidably mounted in the frame to which the other ends of said bands are secured, means guiding said slide elements for movement in a direction parallel to that of the carriage, a bar to which said slide elements are slidably connected, said bar being pivoted on the frame between said slide elements, and means connecting said bar to the grinding-element support whereby the bar is oscillated by reciprocation of the carriage, and said connection being movable whereby its position is varied by adjustment of the grinding-element support on the carriage.

12. A gear-grinding machine having a frame, a carriage reciprocably mounted on the frame, a grinding-element support mounted on the carriage, a grinding element carried by said support, a work-supporting table oscillatably mounted on the frame in position to support a gear blank in engagement with the grinding element, a bar pivoted on the frame between its ends, means connecting points on said bar each'side of its pivot to said table to oscillate the same upon oscillation of the bar, means to oscillate said bar comprising an arm supported upon the carriage and connected to the bar, and means for mounting said grinding-element support on the carriage for adjustment in a direction transverse to the direction of reciprocation thereof, said arm being secured to said support and having a slidable connection with said bar.

13. A gear-grinding machine having a frame, a carriage reciprocably mounted on the frame, a grinding-element support mounted on the carriage, a grinding element carried by said support, a work-supporting table oscillatably mounted on the frame in position to support a gear blank in engagement with the grinding element, a bar pivoted von the frame between its ends, means connecting points on said bar each side of its pivot to said table to oscillate the same upon oscillation of the bar, means to oscillate said bar comprising an arm supported upon the carriage and connected to the bar, means for mounting said grinding-element support on the carriage for adjustment in a direction transverse to the direction of reciprocation thereof, and said arm being secured to the support and pivotally and slidably connected to the bar to vary the amplitude of oscillation of the work support in response to the position of the grinding element with respect to the carriage.

14. A gear-grinding element as in claim 13 wherein the connection between said arm and the pivoted bar is adjustable independently of the position of the grindingelement support on the carriage to vary the amplitude of oscillation of the work support according to the diametral pitch of the gear blank being ground.

15. A gear-grinding machine having a frame, a carriage reciprocably mounted on the frame, a grinding- 7 element support mounted on the carriage, a grinding element carried by said support, a Work-supporting table oscillatably mounted on the frame in position to support a gear blank in engagement with the grinding element, a bar pivoted on the frame between its ends, means connecting points on said bar each side of its pivot to said table to oscillate the same upon oscillation of the bar, means to oscillate said bar comprising an arm supported upon the carriage and connected to the bar, said arm being connected to the supporting means for the grinding element, and a slide element pivotally carried by said arm and slidably engaged with said bar to vary the connection of said arm with the bar with respect to the pivot of the latter.

16. A gear-grinding machine having a frame, a carriage reciprocably mounted on the frame, a grinding-element support mounted on the carriage, a grinding element carried by said support, a work-supporting table oscil- '8 latably mounted on the frame in position to support a gear blank in engagement with the grinding element, a bar pivoted on the frame between its ends, means connecting points on said bar each side of its pivot to said table to oscillate the same upon oscillation of the bar, means to oscillate said bar comprising an arm supported upon the carriage and connected to the bar, said arm being connected to the grinding-element support, a block adjustably connected to said arm and a slide member pivoted to the block and slidably engaged with the bar.

References Cited in the file of this patent UNITED STATES PATENTS 1,135,780 Drummond et a1. Apr. 13, 1915 1,446,777 Wingquist Feb. 27, 1923 2,187,062 Sykes Jan. 16, 1940 

